Most (but not all!) of my searches on Amazon, buying with a Prime account:
- Filter by Prime (for delivery), a max price I will pay, “new” condition, and 4-star rating.
- Sort by Average Customer (product) Reviews.
- Compare the first 5-10 options by actually reading the reviews (sorted for US-based, most recent), looking at images and videos, checking Seller Feedback, and comparing prices and delivery estimates.
- Decide which offer acceptable in price and delivery but also is least likely to arrive damaged due to shoddy pre-FBA packaging and/or NAD.
So most of the time, Seller location is irrelevant. Just because a Seller is US-based does not mean that the products are manufactured domestically.